There have been numerous news announcements, mostly from NASA's Kepler planet hunting observatory, about the discovery of so-called "Earth-like" worlds nestled inside a star's habitable zone.
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Kepler reports on a planet's orbit size, radius, and apparent size. We know next to nothing about the physical characteristics of these worlds including tectonic and magnetic activity, atmosphere composition, axial tilt, and other conditions affecting climate.
But two reliable metrics are pinpointing the location of the planet in the star's habitable zone and the star's age. Unfortunately, stellar ages are not that well know for candidate habitable planets.